917MB / 918MB

Key Features:

These modules not only drive four analog output channels and also feature four discrete outputs for on/off control but also provides Isolation that separates the output, power, and network circuits. Network communication supports the industry-standard RS-485 Modbus RTU protocol.

• Standard Modbus RTU protocol with high-speed RS-485 communication (up to 115K bps)
• 12-bit D/A yields 0.1% of span resolution and accuracy
• Four outputs in a single inch-wide module reduces system costs and saves panel space
• Four discrete outputs enable host-controlled on/off switching
• Heavy-duty 1A solid-state relays provide dependable on/off control of industrial devices
• Self-calibration lowers maintenance costs by reducing periodic manual calibration checks
• Watchdog timers provide a configurable failsafe output state for use when host I/O communication is lost
• Three-way isolation eliminates potential ground loops between power, output and network circuitry
• Self-diagnostics monitor microcontroller activity to detect operational failures (lock-up) and execute a reset to restore communication
• Operating temperature: -25°C to +60°C (-13°F to +140°F), limit 917MB ambient to 50°C maximum for supply voltages less than 15V

Product Details

Input Range


Ambient Temperature Effect
– Better than ±0.001% of output span per °C, or ±1.0uV/°C, whichever is greater.
Ambient Temperature
– Operation (917MB): -25°C to 60°C* (-13°F to 140°F*).
– Operation (918MB): -25°C to 70°C (-13°F to 158°F).
– * Limit 917MB maximum ambient to 50°C (122°F) when using supply voltages less than 15V DC.

Current Output (917MB)


DC Current Output Ranges
– Range user-configured. Range selected applies to all channels.
Output Range Resolution Accuracy (% span)
– 0 to 1mA 0.554% ±2.0% (±0.002mA)
– 0 to 20mA 0.028% ±0.1% (±0.02mA)
– 4 to 20mA 0.035% ±0.1% (±0.02mA)
Maximum Output Current
– 22.5mA DC typical.
– Integral Non-Linearity
– ±0.1% of span or ±2 LSB typical, whichever is larger, for spans equal to or greater than 16mA.
Output Compliance
– 12V minimum, 12.7V typical.
Output Load Resistance Range
– 0 to 630 ohms typical.
Response Time
– 11ms typical into 500 ohms, for measurement to reach 98% of the final value in response to a step command. Actual response time will vary with load.

Voltage Output (918MB)


DC Voltage Output Ranges
– Range user-configured. Selection applies to all channels.
Output Range Resolution Accuracy (% span)
– 0 to 1V 0.274% ±0.6% (±6mV)
– 0 to 5V 0.055% ±0.1% (±5mV)
– 0 to 10V 0.027% ±0.1% (±10mV)
Maximum Output Voltage
– 11.255V DC typical.
Integral Non-Linearity
– ±0.1% of span or ±2 LSB typical, whichever is larger, for spans equal to or greater than 5V.
Output Current
– 0 to 10mA DC maximum.
Output Impedance
– 1 ohm.
Output Short Circuit Protection
– Included.
Response Time
– 110µs rise time typical, 150µs fall time typical, unloaded, for output to reach 98% of the final value in response to a step command. Time varies with load.

Discrete Output


Output Type
– Four independent open drain MOSFET switches with a common return that operate as low-side switches.
Output Voltage Range
– 0 to 35V DC (up to 1A/channel continuous).
– External voltage source required.
Output ON Resistance
– 0.15 ohms maximum.
Output Response Time
– 4.1ms typical, from receipt of command to gate
– Transition of the output MOSFET.

Communication


Supported Modbus Commands
The command/response protocol for communicatingwith this module adheres to the Modbus/RTU standard for the following Modbus Functions.
– Read Coil (Output) Status Report Slave ID
– Read Holding Registers Reset Slave
– Read Input Registers
– Force Single Coil (Output)
– Preset Single Register
– Force Multiple Coils (Output)
– Preset Multiple Registers
LED Indicators
– LEDs indicate power, status, and discrete level/alarm.

Power and Isolation


Power Requirements
– 10 to 36V DC (918MB), 12 to 36V DC (917MB) 22 to 26V AC.
Supply Current
- Supply       Current Draw (917)          Current Draw (918)
– 10V DC      Not Recommended          100mA maximum
– 12V DC      275mA maximum             85mA maximum
– 24V DC     120mA maximum             45mA maximum
– 24V AC     210mA rms maximum     85mA rms maximum

Isolation
– 1500V AC for 60 seconds or 250V AC continuous.
– 3-way isolation between outputs, network, and power circuits.

SOLUTIONS

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