Intech Instruments Ltd

Instrumentation • Monitoring • Control

My Order0
Home | Products | Controllers & Displays | Controllers | Digital Controllers | C91

C91 – 48 x 48mm Digital Controller

Low Cost process and temperature controller.

C91 PID Temperature Controller
C91 Digital Controller - Side View
C91 PID Temperature Controller Back View

C91  Features

  • Fuzzy PID with auto-tune control
  • Dual output: Relay, SSR or Analogue
  • 5Hz sampling rate for fast signal response
  • Supports TC, RTD, mV, mA, and voltage inputs
  • Bright 4-digit LED display for clear readout
  • Digital filter to stabilize fluctuating signals
  • Output 2 can be set as dwell timer function
  • Configurable alarm: high, low, band, dwell
  • Built-in Modbus RTU via RS-232 or RS-485
  • Relay, SSR, or analogue output options
Brand: BRAINCHILD
Usually in stock
Request a quote
Scroll down for product range

C91 PID Temperature Controller | 1/16 DIN PID Solution

The BrainChild C91 Temperature Controller is a compact, high-performance 1/16 DIN controller designed for precise temperature management in industrial automation. Equipped with fuzzy logic auto-tuning PID, it adapts intelligently to process changes, ensuring accurate and stable control.

The C91 supports a wide range of universal input types (TC, RTD, mV, mA) with 18-bit A/D resolution and a fast 5Hz sampling rate. Output configurations include relay, SSR, or analogue retransmission, making it suitable for both heating and cooling applications. Its built-in RS-232/RS-485 Modbus RTU, intuitive 4-key interface, and USB programming port offer seamless system integration and quick setup.

Panel Interface｜LED Display & 4-Key Control

The C91 temperature controller features a simple and functional panel interface designed for quick operation in compact control environments. A 4-digit red LED display provides clear real-time feedback of process values, setpoints, and control status.

Five status indicators on the panel signal essential operating modes:

  • Process Unit Indicator
  • Auto-Tuning Status
  • Manual Mode
  • Deviation Display
  • Output Activation

The device includes 4 tactile membrane buttons for easy configuration of setpoints, parameters, and mode selection, enhancing usability and minimizing setup time.

Input Specs｜Multi-Signal A/D Accuracy

The C91 temperature controller offers flexible universal input compatibility, supporting thermocouples (J, K, T, E, N, R, S), RTDs (PT100 DIN/JIS), and analog signals including 0–50 mV, 0–20 mA, 4–20 mA, 1–5V.

With a high-performance 18-bit A/D converter, it delivers precise readings across all signal types. The input circuit features cold junction compensation, digital filtering, and sensor break detection to ensure measurement stability and safety.

Output Options｜Relay, SSR or Analogue

Selectable relay, SSR voltage or 15-bit analogue output for control

The C91 controller provides flexible dual-output configurations, allowing users to select from relay contacts (2A/240VAC), SSR voltage drive, or analog outputs (0–20 mA, 4–20 mA, 0–10V, 1–5V).

The analogue output features 15-bit D/A resolution, ensuring high signal fidelity. Outputs can be assigned for PID control, alarm signalling, or dwell timer operation, depending on system setup.

Power
90 – 250 VAC, 47 – 63 Hz, 10VA, 5W maximum
111 – 26 VAC / VDC, SELV, Limited Energy, 10VA, 5W maximum

 

Input 1 Characteristics
Resolution 18 bits
Sampling Rate 5 times / second
Maximum Rating -2 VDC minimum, 12 VDC maximum ( 1 minute for mA input )
Temperature Effect ±1.5 uV/ °C for all inputs except mA

input ±3.0 uV/ °C for mA input
Sensor Lead Resistance Effect T/C: 0.2uV/ohm

3-wire RTD: 2.6 °C/ohm of resistance difference of two leads

2-wire RTD: 2.6 °C/ohm of resistance sum of two leads 200nA
Common Mode Rejection Ratio ( CMRR ) 120dB
Normal Mode Rejection Ratio ( NMRR ) 55dB
Sensor Break Detection Sensor open for TC, RTD and mV inputs, Sensor short for RTD input, below 1 mA for 4-20 mA input, below 0.25V for 1 – 5 V input, unavailable for other inputs.
Sensor Break Responding Time Within 4 seconds for TC, RTD and mV inputs, 0.1 second for 4-20 mA and 1 – 5 V inputs.

 

TYPE Range Accuracy@25°C Input Impedance
J -120°C -1000°C (-184°F -1832°F) ±2°C 2.2MΩ
K -200°C -1370°C (-328°F -2498°F) ±2°C 2.2MΩ
T -250°C -400°C (-418°F -752°F) ±2°C 2.2MΩ
E -100°C -900°C (-148°F -1652°F) ±2°C 2.2MΩ
B 0°C -1820°C (32°F -3308°F) ±2°C (200°C – 1820°C) 2.2MΩ
R 0°C-1767.8°C (32°F -3214°F) ±2°C 2.2MΩ
S 0°C -1767.8°C (32°F -3214°F) ±2°C 2.2MΩ
N -250°C -1300°C (-418°F -2372°F) ±2°C 2.2MΩ
L -200°C -900°C (-328°F -1652°F) ±2°C 2.2MΩ
PT100 (DIN) -210°C -700°C (-346°F -1292°F) ±0.4°C 1.3KΩ
PT100 (JIS) -200°C -600°C (-328°F -1112°F) ±0.4°C 1.3KΩ
mV -8mV -70mV ±0.05% 2.2MΩ
mA -3mA -27mA ±0.05% 70.5Ω
V -1.3V-11.5V ±0.05% 302KΩ

 

Output 1 / Output 2
Relay Rating 2A/240 VAC, life cycles 200,000 for resistive load
Pulsed Voltage Source Voltage 5V, current limiting resistance 66

 

Linear Output Characteristics
Type Zero Tolerance Span Tolerance Load Capacity
4-20 mA 3.6-4 mA 20-21 mA 500Ω max.
0-20 mA 0 mA 20-21 mA 500Ω max.
0-5 V 0 V 5-5.25 V 10KΩ min.
1-5 V 0.9-1 V 5-5.25 V 10KΩ min.
0-10 V 0 V 10-10.5 V 10KΩ min.

 

Linear Output
Resolution 15 bits
Output Regulation 0.01 % for full load change
Output Settling Time 0.1 sec. ( stable to 99.9 % )
Isolation Breakdown Voltage 1000VAC
Temperature Effect ±0.0025 % of SPAN / °C

 

Triac ( SSR ) Output
Rating 1A / 240 VAC
Inrush Current 20A for 1 cycle
Min. Load Current 50 mA rms
Max. Off-state Leakage 3 mA rms
Max. On-state Voltage 1.5V rms
Insulation Resistance 1000 Mohms min. at 500 VDC
Dielectric Strength 2500 VAC for 1 minute

 

Alarm ( Output 2 )
Alarm Functions Dwell timer,
Deviation High / Low Alarm,
Deviation Band High / Low Alarm
Process High / Low Alarm
Alarm 1 Relay Form A,Max. rating 2A/240VAC, life cycles 200,000 for resistive load.
Alarm Mode Normal, Latching, Hold, Latching / Hold.
Dwell Timer 0.1 – 4553.6 minutes

 

Data Communication
Interface RS-232 ( 1 unit ), RS-485 ( up to 247 units )
Protocol Modbus Protocol RTU mode
Address 1 – 247
Baud Rate 0.3 ~ 38.4 Kbits/sec
Data Bits 7 or 8 bits
Parity Bit None, Even or Odd
Stop Bit 1 or 2 bits
Communication Buffer 50 bytes

 

Analog Retransmission
Output Signal 4-20 mA, 0-20 mA, 0-1V, 0-5V, 1-5V, 0-10V
Resolution 15 bits
Accuracy ±0.05 % of span ±0.0025 %/ °C
Load Resistance 0 – 500 ohms ( for current output ),10 K ohm minimum ( for voltage output )
Output Regulation 0.01 % for full load change

 

User Interface
Single 4-digit LED Displays 10mm (C21, C91)
Keypad 3 keys(C21), 4 keys(C91)
Programming Port For automatic setup, calibration and testing
Communication Port Connection to PC for supervisory control

 

Control Mode
Output 1 Reverse ( heating ) or direct ( cooling )action
Output 2 PID cooling control, cooling P band 50 ~ 300% of PB, dead band -36.0 ~ 36.0% of PB
ON-OFF 0.1 – 90.0 ( °F ) hysteresis control ( P band = 0 )
P or PD 0 – 100.0 % offset adjustment
PID Fuzzy logic modified , Proportional band 0 ~ 500.0 °C ,
Integral time 0 – 1000 seconds , Derivative time 0 – 360.0 seconds
Cycle Time 0.1 – 100.0 seconds
Manual Control Heat (MV1) and Cool (MV2)
Auto-tuning Cold start and warm start
Failure Mode Auto-transfer to manual mode while sensor break or A-D converter damage
Ramping Control 0 ~ 900.0°F/minute or 0 ~ 900.0 °F/hour ramp rate
Digital Filter Function : First order
Time Constant : 0, 0.2, 0.5, 1, 2, 5, 10, 20, 30, 60 seconds programmable

 

Environmental & Physical
Operating Temperature -10°C ~ 50°C
Storage Temperature -40°C ~ 60°C
Humidity 0 to 90 % RH ( non-condensing )
Insulation Resistance 20 Mohms min. ( at 500 VDC )
Dielectric Strength 2000 VAC, 50/60 Hz for 1 minute
Vibration Resistance 10 – 55 Hz, 10 m/s² for 2 hours
Shock Resistance 200 m/s2( 20 g )
Moldings Flame retardant polycarbonate
Dimensions C21 —50mm(W) X 26.5mm(H) X 110.5mm(D), 98.0 mm depth behind panel
C91 —48mm(W) X 48mm(H) X 94mm(D), 86 mm depth behind panel
Mounting C21 —panel mount, cutout 22 X 45( mm )
C91 —panel mount, cutout 45 X 45 ( mm )
Weight C21 — 120 grams
C91 — 140 grams
Altitude 2000m maximum

 

Approval Standards
Safety UL 61010C-1 , CSA C22.2 No. 24-93 , EN61010-1 (IEC1010-1)
Protective Class NEMA 4X ( IP65 ) front panel for C21,
IP30 front panel for C91, all indoor use,
IP20 housing and terminals
EMC EN61326
C91-(1)-(2)-(3)-(4)-(5)-(6)
 Power Input4: 90 - 250 VAC, 47-63 HZ
5: 11 - 26 VAC or VDC, SELV, Limited Energy
2 Signal Input1: Standard Input
Thermocouple: J, K, T, E, B, R, S, N, L
RTD: PT100 DIN, PT100 JIS 
2: 0 - 60 mV
3: 0 - 1 V
4: 0 - 5 V
5: 1 - 5 V
6: 4 - 20 mA
7: 0 - 20 mA
8: 0 - 10V
9: Special Order
3 Output 10: None
1: Relay rated 2A / 240VAC
2: Pulsed voltage to drive SSR, 5V / 30mA
3: Isolated 4 - 20mA / 0 - 20mA
4: Isolated 1 - 5V / 0 - 5V
5: Isolated 0 - 10V
6: Triac output 1A / 240VAC,SSR
C: Pulsed voltage to drive SSR, 14V/40mA
9: Special order
4 Output 20: None
1: Form A relay 2A / 240VAC
2: Pulsed voltage to drive SSR, 5V / 30mA
3: Isolated 4 - 20mA / 0 - 20mA
4: Isolated 1 - 5V / 0 - 5V
5: Isolated 0 - 10V
6: Triac output, 1A / 240VAC, SSR
7: Isolated 20V / 25mA transducer power supply
8: Isolated 12V / 40mA transducer power supply
9: Isolated 5V / 80mA transducer power supply
A: RS-485 interface (for C91)
C: Pulsed voltage to drive SSR, 14V/40mA
D: Retransmit 4-20mA / 0-20mA (for C91)
E: Retransmit 1-5V / 0-5V (for C91)
F: Retransmit 0-10V (for C91)
B: Special order
5 Communications0: None
1: RS-485 interface
2: RS-232 interface(for C21)
3: Retransmit 4 - 20 mA / 0 - 20 mA(for C21)
4: Retransmit 1 - 5V / 0 - 5V(for C21)
5: Retransmit 0 - 10V(for C21)
9: Special order
6 Display Color0: Red color
1: Green color

Product Range

Product Range:
CodeSpecificationsPriceQuantity
BTC-C91-411101

C91 Digital Controller, Standard input, Relay/Alarm, 90~250Vac

 $289.00
BTC-C91-412101

C91 Digital Controller, Standard input, SSR/Alarm, 90~250Vac

 $289.00
BTC-C91-511101

C91 Digital Controller, Standard input, Relay/Alarm, 11~26Vac/dc

 $289.00
All prices are in NZ$, and GST exclusive and are subject to change without notice.

Intech Instruments Ltd are New Zealand distributors for Brainchild products. Please contact the Brainchild distributor in your country if you require sales or service support for Brainchild products.

Not sure what you need? Ask us anything!

Footer

Intech Christchurch

59 Mandeville Street
Riccarton, Christchurch 8011

Phone: (03) 343 0646

Email: sales@intech.co.nz

Intech Auckland

70 Central Park Drive
Henderson, Auckland 0610

Phone: (09) 827 1930

Email: aucksales@intech.co.nz

Newsletter

Subscribe to our newsletter and get new information every month.