BRUEL & KJAER VIBROCONTROL 8000 - 21.6 Modbus Functions; 21.6.1 Read Relay Channel Status Registers; 21.6.2 Read Channel (or Measurement) Status Registers

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21.6 Modbus Functions
The following Modbus functions are supported in the VC-8000.
Code Name
01
Read Coils (Read Coil Status)
02
Read Discrete Inputs (Read Input Status)
03
Read Multiple Registers (Read Holding Registers)
04
Read Input Registers
07
Read Exception Status
15
Force Multiple Coils
16
Write Multiple Registers (Preset Multiple Registers)
22
Mask Write Register
23
Read/Write Registers
Table 21-2) Modbus Functions
21.6.1 Read Relay Channel Status Registers
You can read the relay channel status. There is no ‘Valid’ or ‘Fault’ status bit for relay channels. If
there is a hardware problem with a relay channel, the rack Not OK relay will trip.
Register Type Data Format Typical
Channel Relay
1 = Active, 0 = Inactive
X
Currently the VC-8000 Modbus function does not include a status bit for the Bypass status of the
relay channel.
21.6.2 Read Channel (or Measurement) Status Registers
You can read alarm status at the Channel level, or the Measurement level.
Channel status reports the overall status of the channel. Measurement status reports the individual
status of each measurement. For example, a Radial Vibration channel has six individual
measurements (Direct, Gap, 1X Amplitude, etc.). Normally, you will only read the (overall) Channel
status.
Most customer sites only read a few of the registers that are available. Table 21-3 shows that users
typically will read Fault, Alert, and Danger status at the Channel level; The other registers do not get
used as much.
Register Type Data Format Typical
Channel Valid
1 = Valid, 0 = Invalid
Channel Fault
1 = Fault, 0 = No Fault
X
Channel Alert
1 = Alert, 0 = No Alert
X
Channel Danger
1 = Danger, 0 = No Danger
X
Channel Trip Multiply
1 = TM Active, 0 = TM Inactive
Channel Bypass
1 = Bypassed, 0 = Not Bypassed
Measurement Valid
1 = Valid, 0 = Invalid
Measurement Alert
1 = Alert, 0 = No Alert
Measurement Danger
1 = Danger, 0 = No Danger
Table 21-3) Channel and Measurement status