TMCM-1021 V1.4 Hardware Manual (Rev. 1.03 / 2014-SEP-30)

9

www.trinamic.com

3.2.1.1 Power supply

For proper operation care has to be taken with regard to power supply concept and design. Due to space

restrictions the TMCM-1021 includes just about 20µF/35V (V1.2) resp. 30µF/35V (V1.4) of supply filter

capacitors. These are ceramic capacitors which have been selected for high reliability and long life time. The

module includes a 24V suppressor diode for over-voltage protection.

Please take the following measures into account in order to avoid serious damage of the device:

Add external power supply capacitors!

It is recommended to connect an electrolytic capacitor of significant size (e.g. 470µF/35V) to

the power supply lines next to the TMCM-1021!

Rule of thumb for size of electrolytic capacitor:

In addition to power stabilization (buffer) and filtering this added capacitor will also reduce

any voltage spikes which might otherwise occur from a combination of high inductance

power supply wires and the ceramic capacitors. In addition it will limit slew-rate of power

supply voltage at the module. The low ESR of ceramic-only filter capacitors may cause

stability problems with some switching power supplies.

Keep the power supply voltage below the upper limit of 28V!

Otherwise the driver electronics will seriously be damaged! Especially, when the selected

operating voltage is near the upper limit a regulated power supply is highly recommended.

Please see also chapter 7, operating values.

There is no reverse polarity protection!

The module will short any reversed supply voltage due to internal diodes of the driver

transistors.

3.2.1.2 RS485

For remote control and communication with a host system the TMCM-1021 provides a two wire RS485 bus

interface. For proper operation the following items should be taken into account when setting up an RS485

network:

1. BUS STRUCTURE:

The network topology should follow a bus structure as closely as possible. That is, the connection

between each node and the bus itself should be as short as possible. Basically, it should be short

compared to the length of the bus.

c:>

node

1

node

n - 1

node

n

Host

Slave

Slave

Slave

RS485

termination

resistor

(120 Ohm)

termination

resistor

(120 Ohm)

}

keep distance as

short as possible

Figure 3.4: Bus structure

2. BUS TERMINATION:

Especially for longer busses and/or multiple nodes connected to the bus and/or high communication

speeds, the bus should be properly terminated at both ends. The TMCM-1021 does not integrate any

termination resistor. Therefore, 120 Ohm termination resistors at both ends of the bus have to be

added externally.