ABB 07AC91 GJR5252300R0101 Analog I/O module
Description:
All analog input modules perform an internal analog-digital conversion. After the conversion, the analog value is represented with 8 or 12 bits, depending on the resolution. For processing and storing this relevant bits (bits which contain the analog information), a 16-bit word is available. All analog output modules perform an internal digital-analog conversion. The digital value before the conversion (consisting of 8 or 12 relevant bits) is stored in a 16-bit word.
The analog input/output module 07AC91 is used as a remote module on the CS31 system bus. It contains 16 analog input/output channels that can be configured in two operating modes:
1. Operating mode "12 bits":
8 input channels, individually configurable ±10 V or 0...20 mA, 12 bit resolution plus 8 output channels, individually  configurable ±10 V or 0...20 mA, 12 bit resolution
2. Operating mode "8 bits":
16 channels, configurable in pairs as inputs or outputs, 0...10 V oder 0...20 mA, 8 bit resolution 
3. The configuration is set with DIL switches.
4. The PLC offers an interconnection element ANAI4_20 for measuring signals of 4...20 mA (refer to 907 PC 331, connection element library).
The module 07 AC 91 uses up to eight input words on the CS31 system bus plus up to eight output words. In the operating mode "8 bits", 2 analog values are packed into one word.
The operating voltage of the unit is 24 V DC. The CS31 system bus connection is electrically isolated from the rest of the module.