Hach 5500sc, Installation Manual

Page: 16 / 70

Connect to the digital inputs
The analyzer can receive a digital signal or contact closure from an external device that causes the
analyzer to skip a sample channel. For example, a flow meter can send a digital signal when the
sample flow is low and the analyzer skips the applicable sample channel. The analyzer continues to
skip the applicable sample channel until the digital signal stops. All sample channels cannot be
skipped. A minimum of one sample channel must be in use.
Note: If all of the sample channels have no sample, the user cannot put the analyzer in shutdown mode with the
digital inputs. To put the instrument into shutdown mode or back into operation remotely, use the optional Modbus
module and write to Modbus register 49937. Write 40007 (decimal) to put the analyzer in shutdown mode. Write
40008 (decimal) to put the analyzer back into operation.
Each digital input can be configured as an isolated TTL type digital input or as a relay/open-collector
type input. Refer to
Figure 12 . By default, the jumpers are set for isolated TTL type digital input (logic
low = 0 to 0.8 VDC and logic high = 2 to 5 VDC; maximum voltage 30 VDC). Refer to Wiring
connections overview on page 12 to connect the device.
Figure 12 Isolated TTL type digital input
1 Jumper (12x) 3 Isolated TTL type digital input
2 Digital input connectors
2
4 Relay/Open-collector type input
Install additional modules
Modules can be added for additional output, relay or communications options. Refer to the
documentation that is supplied with the module.
2
The analyzer uses the DIG6 channel for the level sensor. Do not move the connection and the
jumpers.
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