Rev 20.11.2019
V1.07 - Page 9
Subject to modifications!
romutec Steuer.-und Regelsysteme GmbH Jochsberger Straße 39 D-91592 Buch am Wald
www.romutec.de
Subject to technical changes
5 Description of available modules for MODBus connection
5.1 Digital input module 16 DI eco
The digital input module
romod 16 DI eco
is used
for connecting of up to 16 digital messages.
These include operating messages, error
messages such as frost, filter dirty or fan belt
damaged, and status messages such as damper
positions.
The control of the inputs will be done with 24 V
switched by external dry contacts that are
connected to the module via terminals.
The reference potential is defined via the COM
terminals and can be both, 0 volts and 24 volts.
When using a reference potential of +24 volts, a
control of the digital inputs with 0 V potential can
be realized. The two COM terminals are
connected internally, but not with the GND of the
power supply, i.e. that reference potential for the
inputs has to be connected anyway.
Using the settings in MODBus registers, you can
select open circuit or closed-circuit principle for
each input separately.
The digital inputs can be used as counters, but
only for DC signals. For each input, a prescaler
may be adjusted in order to count, e.g., just every second or third pulse. A subsequent change of the
prescaler also results in a (retroactive) amendment of the corresponding counter values. The pulse
duration must be at least 10 ms to be reliably detected.
For AC control of the inputs, the edge detection has to be delayed via configuration registers (see registers
R1101 and R1111). In case of 50 Hz, this value should be set to at least 40 ms in order to avoid the
counting of false detections. The maximum counter value when using a prescaler of 1 is 65,535 (which is
equivalent to 2
16
-1).
There is a register that displays whether and which DI has changed since the last time this register has
been read. When reading this register, all bits are reset to zero automatically. If a DI's status has altered
several times, e.g. from 0 to 1 and back to 0, a change will be signalized, anyway.
Regarding the system configuration (addressing, maximum number of modules connected to a MODBus
Master interface, installation, connection to the bus etc.), please follow the instructions in the chapter
Configuration
.
Important technical data:
Power supply:
24 V AC or DC, connection via terminals
Current consumption:
max. 150 mA (DC), 220 mA (AC), all DIs loaded
